1. Field of the Invention
The present invention relates generally to the field of control valves for use in a laryngeal prosthesis, or for use in rehabilitating a tracheotomy patient.
2. Description of the Prior Art
The present invention discloses and claims two forms of improved control valves of the type disclosed in U.S. Pat. No. 3,952,335, entitled "Laryngeal Prosthesis," the aggregate disclosure of which is hereby incorporated by reference to amplify the description of structure and operation of the inventive control valves herein disclosed and claimed.
The said U.S. Pat. No. 3,952,335 discloses a unique control valve having a housing defining a chamber therewithin, a tracheal opening adapted to communicate this chamber with the patient's trachea, and a control opening communicating the chamber with ambient atmosphere. A flapper is mounted on the housing within the chamber, and is adapted to move toward and away from the control opening to enable the patient to inhale and exhale through the valve at normal levels, but to pass through the control opening should the patient cough.
However, while the structure disclosed in said patent is believed to be completely satisfactory, it has been realized that a patient's breathing levels may vary as a function of physical activity or exertion. The structure disclosed in said patent does not provide means for adjusting the operational characteristics of the valve to accommodate for different breathing levels of the same patient.
Also, it has been found that the structure disclosed in said patent may be uniquely modified to provide an improved control valve which is adapted to be used to rehabilitate a tracheotomy patient. As persons skilled in this art will realize, a tracheotomy patient is normally provided with a tracheal fistula or stoma through which the patient may breathe. However, when such patient desires to breathe normally through his mouth or nose, he must first cover his tracheal opening. Upon information and belief, tracheotomy patients are normally provided with a "Jackson tube," a "Shiley tube," or equivalent, and common practice has been to simply block such passage through use of a simple cork or other suitable closure device. While this expedient may appear to be adequate, its drawbacks far outweigh its advantages. Should the patient be unable to breathe through his nose or mouth, and gasp for air, the cork will block the tracheal opening. Hence, the cork-expedient, which is understood to be in common practice in hospitals today, requires that the patient or an attendant physically remove the cork or plug to clear the tracheal airway.